Preparation method and application of two-dimensional multilayer D-J type halide perovskite

Abstract

The invention discloses a preparation method and application of two-dimensional multi-layer D-J type halide perovskite, and the two-dimensional multi-layer D-J type halide perovskite is prepared by using aminoethyl pyridine as an interlayer ligand, formamidine as perovskite ions, lead acetate trihydrate as a lead source, a hydrobromic acid aqueous solution as a bromine source and a reaction solvent through a one-step solution method. And carrying out suction filtration, cleaning and drying treatment to obtain a target product. And dissolving the target product in a mixed organic reagent, and obtaining a product with a proper size by using a ligand-assisted anti-solvent method. Different two-dimensional multilayer aromatic DJ halide perovskite can be obtained by selecting aminoethyl pyridine with substituent groups at different positions. The synthesis method is simple, does not need complex instruments, is short in reaction period and is beneficial to large-scale industrial application. The two-dimensional multilayer DJ type perovskite material prepared by the method can be used for preparing benzaldehyde through efficient photocatalytic activation of toluene C (sp3)-H bonds.

Description

Technical Field

[0001] This invention belongs to the field of photocatalyst technology, and relates to a method for preparing a two-dimensional multilayer DJ-type halide perovskite with photocatalytic activity, and also relates to its application as a photocatalyst in the photocatalytic oxidation of toluene to benzaldehyde. Background Technology

[0002] C(sp 3 The direct functionalization of C(sp)-H bonds to form high-value chemical substances is one of the most significant challenges in modern chemistry. Among these, the selective oxidation of toluene to benzaldehyde is an important reaction in the production of fine chemicals, fragrances, and pharmaceutical intermediates. However, the C(sp)-H bonds in toluene... 3 The high bond dissociation energy of the β-H bond (88.5 kcal / mol) and the poor adsorption properties of toluene make its oxidation particularly difficult. Traditional industrial methods, such as thermal oxidation using molecular oxygen under high temperature / high pressure conditions, typically require significant energy consumption and high operating costs. Furthermore, because benzaldehyde is easily over-oxidized to benzoic acid, or even completely mineralized to carbon dioxide, these processes exhibit limited product selectivity. Photocatalysis, however, is a promising green chemistry alternative that utilizes solar energy to oxidize toluene under ambient conditions. This method avoids the use of harsh thermal / pressure conditions while maintaining sustainability and operational safety.

[0003] Among numerous photocatalysts, metal halide perovskites have attracted considerable attention due to their excellent photoelectric properties, including a wide light absorption range, high light absorption coefficient, and long carrier diffusion length. Furthermore, their defect-resistant crystal structure effectively promotes charge transport and suppresses carrier recombination, thereby enabling highly efficient photocatalytic reactions. These unique properties make metal halide perovskites ideal candidate materials for the selective photocatalytic oxidation of toluene to benzaldehyde.

[0004] Recent studies have shown that two-dimensional metal halide perovskites exhibit better environmental stability, and their unique structure endows them with crystal-dependent asymmetric charge transfer potential, promising for efficient photocatalytic reactions. Compared to Ruddlesden-Popper (RP) perovskites with bilayer monoamine organic layers, Dion-Jacobson (DJ) type perovskites lack van der Waals gaps and are connected between adjacent inorganic layers by hydrogen bonds, resulting in stronger interlayer forces. This structural difference enhances their stability and promotes charge transport. Furthermore, with increasing inorganic framework layers, the exciton binding energy of the quasi-two-dimensional perovskite gradually decreases, and the light absorption range gradually expands, thereby improving its photoelectric properties. Therefore, constructing two-dimensional multilayer DJ-type perovskites holds promise for achieving efficient and stable photocatalytic activation of toluene C(sp) 3 Benzaldehyde was prepared by bonding the -H bond. Summary of the Invention

[0005] This invention addresses the aforementioned problems by providing a simple preparation method for novel two-dimensional multilayer DJ-type perovskites and their photocatalytic applications. This preparation method is simple, low-cost, and exhibits excellent photocatalytic activation properties for toluene C(sp...) 3 The synthesis of benzaldehyde via the -H bond is feasible. The process requires no complex equipment and is easy to operate, which is beneficial for large-scale industrial applications.

[0006] The technical solution of this invention is summarized as follows: Using aminoethylpyridine as an interlayer ligand, formamidine acetate (FAac) as a perovskite mineralization ion, hydrated lead acetate as a lead source, and hydrobromic acid aqueous solution as a bromine source, the target product is prepared via a simple one-step solution method. Subsequently, using an antisolvent method with oleylamine and oleic acid as ligands, a target product with a size less than 1 μm is obtained. It exhibits excellent performance as a photocatalyst in the photocatalytic production of formaldehyde from toluene and also has potential application value in other energy development fields.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing two-dimensional multilayer DJ-type halide perovskites, comprising the following steps:

[0009] (1) Dissolve lead acetate trihydrate in hydrobromic acid aqueous solution, then add aminoethylpyridine and formamidine acetate to obtain a large amount of bright yellow precipitate. Then stir and heat the mixture continuously until a clear solution is obtained; wherein, the molar ratio between lead acetate trihydrate, aminoethylpyridine and formamidine acetate is 100 : 3.3 : 36-43;

[0010] (2) Cool the clarified solution obtained in step (1) to room temperature, and obtain the primary target product by separation, washing and drying.

[0011] (3) The primary target product obtained in step (2) is dissolved in a polar aprotic solvent containing oleylamine and oleic acid, and the resulting mixed solution is added dropwise to toluene under vigorous stirring. After centrifugation and washing with toluene multiple times, the target product, two-dimensional multilayer DJ-type halide perovskite, is obtained by drying.

[0012] The preferred process conditions for the above steps are as follows:

[0013] In step (1), the mass fraction of hydrobromic acid in the hydrobromic acid aqueous solution is 48%, and the molar concentration of lead acetate trihydrate is 2 mmol / mL;

[0014] The aminoethylpyridine is selected from any one of 3-(2-aminoethyl)pyridine, 2-aminoethylpyridine (2-APD), and 3-aminoethylpyridine (3-APD), with 3-(2-aminoethyl)pyridine being preferred;

[0015] The mixture is heated to 150 °C.

[0016] In step (2), the drying temperature of the primary target product is 60 °C.

[0017] In step (3), the polar aprotic solvent is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 1:1; the volume ratio of oleylamine to the polar aprotic solvent is 1:117, the volume ratio of oleic acid to the polar aprotic solvent is 1:58.5; and the concentration of the primary target product is 66.7 mg / mL.

[0018] The volume ratio of the resulting mixed solution to toluene was 1:100; the stirring speed of toluene was 1000 rpm; after centrifugation and washing with toluene three times, the target product, two-dimensional multilayer DJ-type halide perovskite, was obtained by drying at 60℃.

[0019] In a second aspect, the present invention provides a two-dimensional multilayer DJ-type halide perovskite prepared by the above method, with 3-(2-aminoethyl)pyridine as an interlayer ligand, and the product is named APDFPB.

[0020] Single-crystal structure analysis revealed that APDFPB belongs to the triclinic crystal system, crystallizes in space group P-1, and exhibits a typical two-dimensional bilayer halide perovskite structure. The formamidinium ion resides in the central vacancy surrounded by PbBr6 octahedra with shared angles, similar to FPB. Furthermore, the shared-angle PbBr6 octahedra exhibit a small-angle tilt, deviating from ideal octahedral symmetry. Simultaneously, the bilayer framework composed of an infinite number of staggered shared-angle PbBr6 octahedra is bounded by a single layer of organic 3-APD. 2+ Cations are separated.

[0021] X-ray diffraction patterns show that APDFPB along (… 00l The crystal faces exhibit strong preferred orientations, indicating a distinct two-dimensional or quasi-two-dimensional structure. Scanning electron microscopy images show that APDFPB exhibits a plate-like crystal morphology. The normalized fluorescence spectrum shows that its exciton ground state emission peak is at 520 nm. Time-resolved fluorescence spectroscopy and UV-Vis absorption spectroscopy show that two-dimensional bilayer halide perovskites have superior photogenerated carrier separation and light absorption capabilities compared to two-dimensional monolayer halide perovskites.

[0022] Using known compounds, two-dimensional monolayer perovskite (3-APD)PbI4 (3-APDPB) and three-dimensional perovskite FAPbBr3 (FPB), as reference materials for reaction performance, the photocatalytic activation of toluene C(sp) under visible light irradiation was investigated. 3Benzaldehyde was prepared by α-H bond synthesis. The results showed that 3-APDFPB exhibited the best photocatalytic performance, significantly increasing the formation rate of benzaldehyde (the main oxidation product) to 1644.7 μmol h⁻¹. -1 g -1 With a selectivity of up to 92%, it is 3-APDPB (652.7 μmol h) -1 g -1 It is 2.5 times that of FPB, far superior to FPB; among them, the catalytic performance is the best at a wavelength of 420 nm.

[0023] Meanwhile, the photo-switching current response and electrochemical impedance spectroscopy under zero bias voltage verified that 3-APDFPB has superior charge separation and transport efficiency; surface photovoltage spectroscopy further proved that 3-APDFPB has better space charge separation capability.

[0024] Therefore, in a third aspect, the present invention provides the application of the above-described two-dimensional multilayer DJ-type halide perovskite in the preparation of a catalyst for the photocatalytic oxidation of toluene to benzaldehyde.

[0025] In a fourth aspect, the present invention provides a catalyst for the photocatalytic oxidation of toluene, comprising an active component and an auxiliary material acceptable in the field of catalysts, wherein the active component is the two-dimensional multilayer DJ-type halide perovskite described above.

[0026] In a fifth aspect, the present invention provides a method for photocatalytic oxidation of toluene to produce benzaldehyde, comprising the following steps: in a transparent sealed reactor, using pure toluene as the reaction liquid, using the above-mentioned photocatalytic oxidation catalyst of toluene as the photocatalyst, using air as the reaction atmosphere, using a white LED as the light source, and using side irradiation.

[0027] The light source wavelength is selected as follows: 420 nm < λ < 780 nm, preferably 420 nm; the illuminance is 150 mW / cm². 2 .

[0028] The liquid products of the selective oxidation of toluene were analyzed by high-performance liquid chromatography (HPLC, Shimazu LC-40D). Acetonitrile was used as mobile phase A, and 0.02 wt% formic acid aqueous solution was used as mobile phase B to separate the reactants and products. The volume ratio of A:B was set to 4:6. The UV detector wavelength was 250 nm, the column temperature was 35℃, the flow rate was 1 mL / min, and the injection volume was 10 μL. The results showed that the formation rate of benzaldehyde was 1644.7 μmol h⁻¹. -1 g -1 The selectivity rate was 92%;

[0029] After 6 cycles (3 hours each), the yield of benzaldehyde decreased by only 7.5%, while the selectivity remained almost unchanged and the stability was good.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) A novel two-dimensional multilayer DJ-type halide perovskite was synthesized by a simple solution method. This synthesis method is simple to operate, low in cost, does not require complex instruments, has a short reaction cycle, and can be synthesized in large quantities, which is beneficial for large-scale industrial applications.

[0032] (2) Using novel two-dimensional multilayer DJ-type halide perovskite as a photocatalytic activator for toluene C(sp) 3 The catalyst, denoted as )-H, exhibits excellent photocatalytic activation properties for toluene C(sp)-H. 3 The selectivity and reactivity of benzaldehyde production by 3-(2-aminoethyl)pyridine were investigated; the benzaldehyde formation rate was 1644.7 μmol / h. -1 g -1 The selectivity rate was 92%;

[0033] (3) All reagents used in the preparation process are commercial products and do not require further processing;

[0034] (4) The synthesis method is simple and the obtained materials are easy to use, which is conducive to their application in industrial production. They also have potential application value in other energy development and environmental protection fields. Attached Figure Description

[0035] Figure 1 The single-crystal structures of 3-APDFPB prepared in Example 1, and monolayer two-dimensional halide perovskite (3-APD)PbI4 (3-APDPB) and three-dimensional halide perovskite FAPbBr3 (FPB) are shown, where a, b, and c refer to 3-APDPB, 3-APDFPB, and FPB, respectively.

[0036] Figure 2 The X-ray diffraction patterns of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown, where a, b and c refer to 3-APDPB, 3-APDFPB and FPB, respectively.

[0037] Figure 3 Scanning electron microscope images of 3-APDPB, 3-APDFPB and FPB halide perovskite nanocrystals are shown, where a, b and c refer to 3-APDPB, 3-APDFPB and FPB, respectively.

[0038] Figure 4Normalized fluorescence spectra of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown.

[0039] Figure 5 Time-resolved fluorescence spectra of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown;

[0040] Figure 6 The UV-Vis absorption spectra (a) and corresponding Tauc plot spectra (b) of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown.

[0041] Figure 7 The ultraviolet photoelectron spectra (a) and energy level diagrams (b) of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown.

[0042] Figure 8 The photocatalytic activation of toluene C(sp) by 3-APDPB, 3-APDFPB, and FPB halide perovskite nanocrystals under visible light irradiation was demonstrated. 3 )-H bond preparation of benzaldehyde yield (a); 3-APDFPB photocatalytic activation of toluene C(sp) at different monochromatic wavelengths 3 (b) Graph of benzaldehyde production rate prepared by )-H bond and its working stability under visible light (c);

[0043] Figure 9 The photo-switching current response (a) and electrochemical impedance spectroscopy (b) of 3-APDPB, 3-APDFPB and FPB halide perovskites at zero bias are shown.

[0044] Figure 10 The surface photovoltage spectra of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown.

[0045] Among them, the known compounds two-dimensional monolayer perovskite (3-APD)PbI4 (3-APDPB) and three-dimensional perovskite FAPbBr3 (FPB) are used as reference materials for reaction performance. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The “range” disclosed herein takes the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this way are inclusive and composable; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 100–140 and 500–900 are listed for a specific parameter, it is expected that ranges of 100–140 and 500–900 are also expected. Furthermore, if the minimum range values ​​are listed as 1 and 2, and if the maximum ranges are listed as 3, 4, and 5, then the following ranges are all expected: 1–2, 1–4, 1–5, 2–3, 2–4, and 2–5.

[0048] In this invention, unless otherwise specified, the numerical range "a ~ b" represents an abbreviation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0 ~ 5" means that all real numbers between "0 ~ 5" have been listed in this document, and "0 ~ 5" is simply an abbreviation of these numerical combinations.

[0049] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0050] Example 1

[0051] I. Preparation of (3-APD)(FA)Pb2Br7 photocatalyst

[0052] 0.379 g (10 mmol) of lead acetate trihydrate was dissolved in 5 mL of hydrobromic acid aqueous solution, and 40 μL (0.33 mmol) of 3-(2-aminoethyl)pyridine and 0.445 g (4.3 mmol) of formamidin acetate were added, resulting in a large amount of bright yellow precipitate. The mixture was heated at 150 °C with continuous stirring until a clear solution was obtained. The clear solution was then cooled to room temperature, and the target product was obtained by separation, washing, and drying at 60 °C. 200 mg of the obtained product was dissolved in 3 mL of a 1:1 (v / v) mixture of N,N-dimethylformamide and dimethyl sulfoxide (containing 25 μL of oleylamine and 50 μL of oleic acid). 100 μL of the resulting solution was added dropwise to 10 mL of toluene under vigorous stirring (1000 rpm), and the product was centrifuged, washed three times with toluene, and dried at 60 °C to obtain a bright yellow target product with a size less than 1 μm.

[0053] II. Performance Characterization Test

[0054] All photocatalytic performance studies were conducted using a CEL-PCRD300-12 photochemical reactor, with known compounds such as two-dimensional monolayer perovskite (3-APD)PbI4 (3-APDPB) and three-dimensional perovskite FAPbBr3 (FPB) used as reference materials. The reactor was a 50 mL vertical reactor equipped with a sealing plug. Pure toluene was used as the reaction solution, 3-APDPB as the photocatalyst, the reaction atmosphere was air, the light source was a white LED (420 nm < λ < 780 nm), the irradiation method was side irradiation, and the light intensity was 150 mW / cm². 2 The liquid products of selective oxidation of toluene were analyzed by high-performance liquid chromatography (HPLC, Shimazu LC-40D). Acetonitrile was used as mobile phase A, and 0.02 wt% formic acid aqueous solution was used as mobile phase B to separate the reactants and products. The volume ratio of A:B was set to 4:6. The UV detector wavelength was 250 nm, the column temperature was 35℃, the flow rate was 1 mL / min, and the injection volume was 10 μL.

[0055] Figure 1 Single-crystal structures of a monolayer two-dimensional halide perovskite (3-APD)PbI4 (3-APDPB), 3-APDFPB from Example 1, and a three-dimensional halide perovskite FAPbBr3 (FPB) are shown. a, b, and c represent 3-APDPB, 3-APDFPB, and FPB, respectively, where 3-APDPB and FPB are known references. 3-APDFPB belongs to the triclinic crystal system, crystallizes in space group P−1, and exhibits a typical two-dimensional bilayer halide perovskite structure. The formamidinium ion resides in the central vacancy surrounded by PbBr6 octahedra, similar to FPB. Furthermore, the angularly aligned PbBr6 octahedra exhibit a small-angle tilt and deviate from ideal octahedral symmetry. Simultaneously, the bilayer framework composed of an infinite number of interlaced angularly aligned PbBr6 octahedra is surrounded by a monolayer of organic 3-APD. 2+ Cations are separated;

[0056] Figure 2 X-ray diffraction patterns of 3-APDPB, 3-APDFPB, and FPB halide perovskite crystals are shown, with a scanning range of 5°–50°. a, b, and c represent 3-APDPB, 3-APDFPB, and FPB, respectively. It can be seen that the diffraction peaks correspond one-to-one with the diffraction peaks simulated based on the CIF file, and there are no impurity phases. The 3-APDPB and 3-APDFPB powders show diffraction patterns along (…). 00l The crystal planes exhibit strong preferred orientations, indicating a distinct two-dimensional or quasi-two-dimensional structure. Single-crystal X-ray diffraction crystallographic data for 3-APDFPB material are shown in Table 1.

[0057] Table 1 Single-crystal X-ray diffraction crystallographic data of 3-APDFPB materials

[0058]

[0059]

[0060] Figure 3 Scanning electron microscope images of 3-APDPB, 3-APDFPB and FPB halide perovskite nanocrystals are shown, where a, b and c refer to 3-APDPB, 3-APDFPB and FPB, respectively; among them, 3-APDPB and 3-APDFPB have similar size plate-like crystal morphology.

[0061] Figure 4 Normalized fluorescence spectra of 3-APDPB, 3-APDFPB, and FPB halide perovskite crystals are shown. Their exciton ground-state emission peaks gradually redshift to 480 nm, 520 nm, and 550 nm, respectively, indicating a gradual narrowing of the band gap.

[0062] Figure 5 The time-resolved fluorescence spectra of 3-APDPB, 3-APDFPB and FPB halide perovskite crystals are shown. It can be seen that the photogenerated carrier lifetime of these materials is: FPB>3-APDFPB>3-APDPB, which further illustrates that two-dimensional bilayer halide perovskites have better photogenerated carrier separation ability than two-dimensional monolayer halide perovskites.

[0063] Figure 6 The UV-Vis absorption spectra (a) and corresponding Tauc plots (b) of 3-APDPB, 3-APDFPB, and FPB halide perovskite crystals are shown. As shown in the figure, the optical band gaps of 3-APDPB, 3-APDFPB, and FPB are 2.79, 2.62, and 2.21 eV, respectively, indicating that two-dimensional bilayer halide perovskites have superior light absorption capabilities compared to two-dimensional monolayer halide perovskites.

[0064] Figure 7 The ultraviolet photoelectron spectra (a) and energy level diagrams (b) of 3-APDPB, 3-APDFPB, and FPB halide perovskite crystals are shown. The valence band top energies of 3-APDPB, 3-APDFPB, and FPB relative to the standard hydrogen electrode are 1.15, 1.64, and 1.63 eV, respectively, and the conduction band bottom energies relative to the standard hydrogen electrode are −1.64, −0.98, and −0.58 eV, respectively.

[0065] Figure 8The photocatalytic activation of toluene C(sp) by 3-APDPB, 3-APDFPB, and FPB halide perovskite nanocrystals under visible light irradiation was demonstrated. 3 )-H bond preparation of benzaldehyde yield (a); 3-APDFPB photocatalytic activation of toluene C(sp) at different monochromatic wavelengths 3 The production rate of benzaldehyde via the 3-H bond is shown in diagram (b), and its stability under visible light is shown in diagram (c). The results show that 3-APDFPB exhibits the best photocatalytic performance, significantly increasing the production rate of benzaldehyde (the main oxidation product) to 1644.7 μmol h⁻¹. -1 g -1 With a selectivity of up to 92%, it is 3-APDPB (652.7 μmol h) -1 g -1 It is 2.5 times that of FPB, far superior to that of 3-APDFPB. Meanwhile, wavelength has a certain influence on the catalytic performance of 3-APDFPB; within the test range, the catalytic performance is best at a wavelength of 420 nm, with a benzaldehyde formation rate reaching 904.48 μmol / h. -1 g -1 The selectivity was 82.3%; after 6 cycles (3 hours each) under visible light, the yield of benzaldehyde decreased by only 7.5% with almost no decrease in selectivity, indicating good stability.

[0066] Figure 9 The photo-switching current response (a) and electrochemical impedance spectroscopy (b) of halide perovskite crystals of 3-APDPB, 3-APDFPB, and FPB under zero bias are shown. The results show that the chopping photocurrent of 3-APDFPB is significantly higher than that of 3-APDPB and FPB. Furthermore, 3-APDFPB exhibits a smaller semicircle in the electrochemical impedance spectroscopy, verifying its superior charge separation and transport efficiency.

[0067] Figure 10 The surface photovoltage spectra of 3-APDPB, 3-APDFPB, and FPB halide perovskite crystals are shown. As shown in the figure, 3-APDFPB exhibits a significantly higher surface photovoltage than 3-APDPB and FPB, further demonstrating that 3-APDFPB has better space charge separation capability.

[0068] Example 2

[0069] 0.379 g of lead acetate trihydrate was dissolved in 5 mL of hydrobromic acid aqueous solution, followed by the addition of 40 μL of 2-aminoethylpyridine (2-APD) and 0.405 g of FAac, resulting in a large amount of bright yellow precipitate. The mixture was then continuously stirred and heated until a clear solution was obtained. The clarified solution was then cooled to room temperature, and the target product was obtained by separation, washing, and drying. 200 mg of the obtained product was dissolved in 3 mL of a 1:1 (v / v) mixture of N,N-dimethylformamide and dimethyl sulfoxide (containing 25 μL of oleylamine and 50 μL of oleic acid). 100 μL of the resulting solution was added dropwise to 10 mL of vigorously stirred toluene, and the mixture was centrifuged, washed three times with toluene, and dried at 60 °C to obtain a bright yellow target product with a size less than 1 μm. The characteristics and properties are similar to those in Example 1.

[0070] Example 3

[0071] 0.379 g of lead acetate trihydrate was dissolved in 5 mL of hydrobromic acid aqueous solution, followed by the addition of 40 μL of 3-aminoethylpyridine (3-APD) and 0.375 g of FAac, resulting in a large amount of bright yellow precipitate. The mixture was then continuously stirred and heated until a clear solution was obtained. The clear solution was then cooled to room temperature, and the target product was obtained by separation, washing, and drying. 200 mg of the obtained product was dissolved in 3 mL of a 1:1 (v / v) mixture of N,N-dimethylformamide and dimethyl sulfoxide (containing 25 μL of oleylamine and 50 μL of oleic acid). 100 μL of the resulting solution was added dropwise to 10 mL of vigorously stirred toluene, and the product was centrifuged, washed three times with toluene, and dried at 60 °C to obtain a bright yellow target product with a size less than 1 μm. The characteristics and properties are similar to those in Example 1.

[0072] The material obtained in this invention is applied to the photocatalytic activation of toluene C(sp) 3 Benzaldehyde was prepared by photocatalytic activation of toluene C(sp3)-H bonds. A novel two-dimensional aromatic multilayer DJ-type halide perovskite was prepared for the photocatalytic activation of toluene C(sp3)-H bonds to prepare benzaldehyde. The preparation was carried out at room temperature and pressure. Pure toluene was used as the reaction solution in a 50 mL vertical glass reactor (equipped with a sealed stopper). The prepared novel two-dimensional multilayer DJ-type halide perovskite was used as the photocatalyst. The reaction atmosphere was air, and the light source was a white LED (420 nm < λ < 780 nm) with side irradiation at an intensity of 150 mW / cm². 2 The above description is merely a preferred embodiment of the present invention. All equivalent variations and modifications made within the scope of the claims of this invention should be considered within the scope of this invention.

[0073] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for preparing two-dimensional multilayer DJ-type halide perovskite, characterized in that, Includes the following steps: (1) Dissolve lead acetate trihydrate in hydrobromic acid aqueous solution, then add aminoethylpyridine and formamidine acetate to obtain a large amount of bright yellow precipitate. Then stir and heat the mixture continuously until a clear solution is obtained; wherein, the molar ratio between lead acetate trihydrate, aminoethylpyridine and formamidine acetate is 100 : 3.3 : 36-43; (2) Cool the clarified solution obtained in step (1) to room temperature, and obtain the primary target product by separation, washing and drying. (3) The primary target product obtained in step (2) is dissolved in a polar aprotic solvent containing oleylamine and oleic acid, and the resulting mixed solution is added dropwise to toluene under vigorous stirring. After centrifugation and washing with toluene multiple times, the target product, two-dimensional multilayer DJ-type halide perovskite, is obtained by drying.

2. The method for preparing two-dimensional multilayer DJ-type halide perovskite according to claim 1, characterized in that: in, In step (1), the mass fraction of hydrobromic acid in the hydrobromic acid aqueous solution is 48%, and the molar concentration of lead acetate trihydrate is 2 mmol / mL; Aminethylpyridine is selected from any one of 3-(2-aminoethyl)pyridine, 2-aminoethylpyridine (2-APD), and 3-aminoethylpyridine (3-APD); The mixture is heated to 150 °C.

3. The method for preparing two-dimensional multilayer DJ-type halide perovskite according to claim 2, characterized in that: in, In step (2), the drying temperature of the primary target product is 60 °C.

4. The method for preparing two-dimensional multilayer DJ-type halide perovskite according to claim 1, characterized in that: in, In step (3), the polar aprotic solvent is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 1:1; The volume ratio of oleylamine to the polar aprotic solvent is 1:117, and the volume ratio of oleic acid to the polar aprotic solvent is 1:58.

5. The concentration of the primary target product was 66.7 mg / mL.

5. The method for preparing two-dimensional multilayer DJ-type halide perovskite according to claim 1, characterized in that: in, In step (3), the volume ratio of the mixed solution to toluene is 1:100; the stirring speed of the toluene is 1000 rpm. The target product, a two-dimensional multilayer DJ-type halide perovskite, was obtained by centrifugation, washing with toluene three times, and drying at 60°C.

6. A two-dimensional multilayer DJ-type halide perovskite, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the two-dimensional multilayer DJ-type halide perovskite according to claim 6 in the preparation of a catalyst for the photocatalytic oxidation of toluene to benzaldehyde.

8. A catalyst for the photocatalytic oxidation of toluene, characterized in that, Includes active components and auxiliaries acceptable in the field of catalysts, wherein the active component is the two-dimensional multilayer DJ-type halide perovskite as described in claim 6.

9. A method for photocatalytic oxidation of toluene to benzaldehyde, characterized in that, The process includes the following steps: in a transparent sealed reactor, pure toluene is used as the reaction liquid, the catalyst for photocatalytic oxidation of toluene as described in claim 8 is used as the photocatalyst, the reaction atmosphere is air, the light source is a white LED, and the irradiation method is side irradiation.

10. The method for photocatalytic oxidation of toluene to benzaldehyde according to claim 9, characterized in that: in, The light source wavelength is selected as follows: 420 nm < λ < 780 nm; the illuminance is 150 mW / cm². 2 .

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